This invention relates to a vehicle steering system, and in particular to a steering system or vehicles with independent suspension.
Steering systems for conventional beam axle trucks are arranged with ball jointed rod ends which cater for the angular rotation of the wheels as shown typically in FIG. 1 of the attached drawings. Each wheel is fitted with a steering arm 1 and these steering arm 1 are connected to each other by a track rod 2 by means of ball joints 3.
In independent suspension systems, each wheel can move in the vertical direction independently of the other wheel. In such systems a single track rod is not sufficient and an arrangement typically as shown in FIG. 2 of the attached drawings is required. In this case the track rod is replaced by a system which provides an interconnection between the wheels whilst allowing independent vertical motion of the wheels. This is achieved by means of links 4 and 5 which replace the one piece track rod described previously in FIG. 1. The links 4 are fitted with ball joints 6 at each end to allow vertical articulation of the wheel. Such systems or variations thereof are commonly used in automotive independent suspension systems. In most conventional systems wheel vertical articulation is relatively small and the links 4 are relatively long and so very large angular movement of the articulation joints 6 is not required.
In high performance independent suspension systems for high mobility vehicles, wheel movements in excess of 350 mm are commonly required. With such wheel movements large joint articulations in excess of 40xc2x0 are frequently required. This is beyond the capacity of normal steering ball joints and requires the use of special spherical joints with high angular capacity and complicated sealing. Satisfactory sealing for all conditions is very difficult to achieve for such high angular movement. These joints are also relatively complex and expensive to produce.
The present invention is directed towards overcoming these problems.
It is an object of the invention to eliminate the need for special spherical joints while permitting high articulation with relatively simple sealing.
The objects of the invention are achieved by replacing the special spherical joints by a connector in which opposite ends of the connector are rotatable relative to each other. Preferably the connector is of two-part construction said parts being pivotally interconnected.
According to the invention there is provided for a connector for a vehicle steering system, the connector for attachment between a steering link and a steering arm on a wheel to accommodate vertical movement and swivelling of the wheel in use, characterised in that the connector has opposite ends for attachment to the steering link and steering arm, said opposite ends of the connector being rotatable relative to each other using only single axis pivots.
In one embodiment of the invention the pivot axes intersect.
In another embodiment a pivot joint at one end of the connector comprises a swivel pin rotatably mounted in a complimentary housing.
In a further embodiment pivot joints at opposite ends of the connector each comprise a swivel pin rotatably mounted in a complimentary housing.
In another embodiment the connector is hinged intermediate the ends of the connector.
In another embodiment the swivel pin has a journal portion for engagement with an associated bearing in the housing.
Preferably at least portion of a pin has a screw thread for complementary engagement with an associated threaded bore portion of the housing. In another embodiment the pin engages the housing by means of a complementary screw thread.
In another embodiment the connector comprises a swivel pin and associated housing at an outer end of the connector for engagement between the connector and the steering arm, a pivot pin being provided at an inner end of the connector for connection to an associated eye attached to the steering link.
In a further embodiment the connector comprises a pair of hingedly connected swivel pins, comprising a first swivel pin which rotatably engages an associated housing on the steering arm and a second swivel pin which rotatably engages an associated housing on the steering link.
In another embodiment one swivel pin has a forked end for reception of an end of the second swivel pin which has an eye which engages between the forks, a pivot pin engaging through the forks and eye to hingedly connect the swivel pins.
In another aspect the invention provides a vehicle steering system incorporating a connector.
In a still further aspect the invention provides a vehicle incorporating a steering system.